A three-year-old boy whose father suffered a seizure took to a main road on his toy truck to raise the alarm.
Stefan Snowden, from Twenty, Lincolnshire, covered a quarter of a mile on his Paw Patrol truck after his father, Marc, fell ill at home.
He was then spotted by two women on the A151 main road as passing traffic beeped and drove round the youngster.
Stefan later told police his "daddy was poorly".
His mother, Carla Neve, 25, said Stefan had set off from the family's home after Mr Snowden, 28, suffered a seizure on the sofa at home.
"He loses consciousness when he has a seizure," she said, as she praised her son for his bravery.
"Stefan knows how to get out of the front door and must have gone to get his truck," the couple said.
Insp Rachel Blackwell, from Lincolnshire Police, also praised the women who stepped in to help, one of whom rushed to stop the traffic after she spotted Stefan on the busy main road linking Spalding and Bourne.
"Without her speedy actions the child could have been seriously injured or worse," she said.
Another woman took the youngster into her home and kept him entertained until police arrived.
Insp Blackwell added Mr Snowden was now "doing fine" and the family were "so thankful to these two amazing people" who helped their son.